update solution tests

Author: jaimesouza

tests/test_solution.py

@@ -136,7 +136,4 @@ def test_solution(self, dimension, space_order, language, density):
         # load the reference result
         u_ref = np.load(ref_file)
 
-        if density:
-            assert np.allclose(u, u_ref, atol=1e-04)
-        else:
-            assert np.allclose(u, u_ref, atol=1e-05)
+        assert np.allclose(u, u_ref, atol=1e-05)